The invention relates to a hyperbaric transfer system for transferring individuals under high pressure conditions. Preferably, the system is used in transferring divers undergoing decompression from an offshore decompression chamber to an onshore hyperbaric facility.
Offshore diving operations have brought tremendous problems to divers who are called upon to perform heavy construction work at depths and in diving conditions that border on the limits of underwater technology. The risk of serious trauma exists and with the use of saturation techniques there is the danger of acute illness while a diver is under pressure.
Divers who have worked at great depths for considerable amounts of time must undergo decompression for periods up to two weeks. Normally, the decompression process takes place in a conventional decompression chamber on the offshore rig. However, in certain emergency situations it may become necessary or desireable for the diver undergoing decompression to leave the offshore rig.
One such instance is during rig abandonment situations, such as a blow out, fire or collision. Under current practice in such a situation divers remain in the decompression chamber on the rig or the decompression chamber is jettisoned into the water. In some instances, the divers are transferred to a diving bell which is lowered into the sea. However, these practices are not reliable, safe or efficient.
Leaving the decompression chamber on the offshore rig is unsafe since the divers in the chambers are helpless and cannot protect themselves from the danger of the emergency situation. However, the alternative of transferring the occupants to a diving bell or jettisoning the chamber into the sea is even less desireable. The process is slow and dangerous. Since it is so dangerous, this step cannot be taken as a conservative course of action to provide a maximum amount of safety for the divers even though there is no immediate danger. Therefore, this step is taken only when it is clear that the rig will be lost. In jettisoning the chamber or placing the diving bell in the sea, the guidelines securing the chamber or bell to the rig are cut and the divers must rely on a later attempt to retrieve them by a supply or rescue ship. However, recovery is contingent on the availability of a rescue ship, weather conditions, sea conditions, as well as containment of the original emergency which caused the rig abandonment.
Another instance in which it would be desireable to leave the offshore rig is if a diver has been seriously injured and needs medical care. Until now the injured diver has received treatment on the offshore rig. However, treatment is often unsatisfactory. A doctor has to be located and transported to the offshore rig. Once the doctor arrives, the equipment to properly treat the patient is not always available on the rig. If the patient needs an operation, the conditions, facilities and equipment on an offshore rig do not compare with an onshore hospital. Inherent in an offshore decompression chamber are excessive noise and vibration levels, possibly poor communications and lighting, the absence of immediate specialist treatment facilities and greater risk of infection. If hospitalization is required, the diver must wait until the normal decompression schedule is complete so he can be transferred to an onshore hospital.
Although the diver's safety is of utmost importance, economic considerations are also present. If the decompression chamber of an off-shore rig is tied up for days while in use in an attempt to save a diver's life, the decompression chamber is unavailable for normal operations. If rig operations are held up, expenses for such an immobilization could average $50,000 per day.